British police say they have arrested Russian tycoon Boris Berezovsky for alleged fraud.

Russian authorities have been asking British police to arrest and extradite Mr. Berezovsky since last November. The former Kremlin insider has been living in self-imposed exile in Britain.

Monday, police in London finally acted on at least one of those requests, briefly arresting Mr. Berezovsky before releasing him on bail, pending a court appearance on April 2.

The police did not formally announce the arrest until Tuesday and said that a business associate of Mr. Berezovsky's, Yuly Dubov, also was taken into custody. But like Mr. Berezovsky, he too was later released.

Both men are wanted by Russian authorities in connection with charges that they defrauded the administration of Russia's Samara region of nearly $2 billion while managing a car company called Logovaz.

Mr. Berezovsky founded the company in the early 1990s, and Mr. Dubov was his co-director and former chief executive of the company.

The Russian charges focus on the theft of cars from Logovaz, which was the official dealer for Russia's largest carmaker, AvtoVaz.

Mr. Berezovsky has long denied the series of charges against him, saying they are politically-motivated retaliation for his criticism of Russian President Vladimir Putin. He maintained that stance in an interview with Russia's Echo Moscow radio station, shortly after he was released from custody in London.

Mr. Berezovsky also expressed confidence that British authorities would not extradite him to Russia. He said he believes he will live out the rest of his days as a political refugee.

Mr. Berezovsky is one of Russia's so-called oligarchs. He earned the term by amassing substantial personal wealth as a political insider during former President Boris Yeltsin's years as president.

Mr. Berezovsky later used that wealth to help fund President Putin's successful campaign for the presidency. But the two men later fell out and the Russian oil and media magnate fled Russia for a life of exile in Britain in the late 1990s, when Russian prosecutors first launched fraud charges against him.

Mr. Berezovsky remains a fervent critic of the Russian political leadership and has lately become an outspoken advocate for peace talks with Chechen separatist rebels.